Compressor valve arrangement

ABSTRACT

A compressor valve arrangement having a device for regulating delivery quantities and wherein a valve plate can be raised from a valve seat against a closing force by means of control pistons displaceable in cylinder bores in the valve seat.

United States Patent lnventor Friedrich Bauer Vienna, Austria Appl. No.864,392 1 Filed Oct. 7, 1969 Patented Oct. 19, 1971 Assignee HoerbigerVentilwerke Aktiengesellschaft Priority Oct. 16, 1968 Austria A10l29/68COMPRESSOR VALVE ARRANGEMENT 5 Claims, 3 Drawing Figs.

US. Cl 137/522, 251/63.4, 417/446 Int. Cl F16k 15/00 Field of Search417/297,

References Cited UNITED STATES PATENTS McCarroll Holland Sahle HirschMikina Hackbart."

Ott et a1 FOREIGN PATENTS 4/1955 ltaly 1.

Primary Examiner Laverne D. Geiger Assistant ExaminerDavid J. ZobkiwAtt0mey--Watson, Cole, Grindle & Watson 251/58 X 251/58 X 417/298 X417/298 137/522 X 417/446 137/522X ABSTRACT: A compressor valvearrangement having a device for regulating delivery quantities andwherein a valve plate can be raised from a valve seat against a closingforce by means of control pistons displaceable in cylinder bores in thevalve seat.

COMPRESSOR VALVE ARRANGEMENT BACKGROUND OF THE INVENTION It is known forvalves of piston type compressors to be provided with devices which makeit possible to raise the valve plate from the valve seat and keep itopen, in order to permit starting up of the compressor under no-loadconditions, and possibly also regulation of the delivery quantity duringoperation. The induction valves are generally kept open by these devicesso that the medium drawn in is again forced back into the induction lineduring the pressure stroke of the compres sor piston. In the same way,it is also possible to bring about regulation of the delivery quantityby raising the pressure valve plates, the compressed gas thus flowingback into the cylinder and preventing opening of the induction valve.

In known types of valve having control pistons acted upon by a pneumaticor hydraulic medium for raising the valve plate, the control pistons aredisposed in cylinder bores the axes of which are perpendicular to theplane of the valve plate to be raised. The control pistons are thusdisplaceable in the direction of movement of the valve plate and actupon the latter either directly or by means of lifting pins fastened onpistons.

In the other known constructional types, in which the valve plate israised by springs acting upon it via lifting pins and the pressuremedium actuated control pistons serve to pull back the spring-loadedlifting pins from the valve plate, the cylinder bores of the controlpistons are also disposed in the lifting direction. Since, as a resultof the small stroke of the valve plate, which is of the order ofmagnitude of about 1 mm., the adjusting path of the control pistons isequally small, it is necessary, for the purpose of achievingsufficiently great lifting forces at a specific control pressure toprovide either a plurality of control pistons or relatively largecontrol pistons. In many cases, the space necessary for this purpose isnot available in the valve seat itself, so that bulky designs, withlifting pins disposed on the control pistons, are required. In addition,in the event of the regulating device requiring too much room, there isa disadvantageous restriction of the valve cross section available forthe passage of the medium delivered.

The invention has the aim of improving compressor valves with aregulating device of the type, mentioned particularly in respect of thespace requirement of the regulation device.

SUMMARY OF THE INVENTION According to the invention, a compressor valvearrangement is provided, comprising a valve seat having flow channelstherein controlled by a valve plate, spring means arranged to press thevalve plate on to the valve seat and lifting means arranged to raise thevalve plate from the valve seat against closing forces acting upon thevalve plate, wherein the lifting means comprises control pistonsdisplaceable in cylinder bores in the valve seat, the cylinder boresbeing disposed in the valve seat with their axes inclined in relation tothe direction of movement of the valve plate, and the control pistonseach have a control face inclined to the axis of the piston and indriving connection with the valve plate, preferably with theinterposition of a lifting piece.

As a result of this arrangement of the cylinder bores, the spatialaccommodation of the regulating device in the valve seat is more easilypossible, because the cylinder bores with the control pistons do nothave to be disposed precisely below the valve plate with axes extendingin the direction of movement of the latter. Furthermore, a ratio betweenthe lifting movements of the control pistons and the valve plate may beachieved, in which the path covered by the piston during the liftingprocess may be considerably greater than the stroke of the valve plate.As a result, sufficiently great lifting forces can be achieved, evenwith a smaller number of control pistons or with the aid of pistonshaving a smaller diameter, so that compared with known valves the spacerequirement of the entire regulating device can be substantially reducedwhile the lifting forces remain the same, or conversely, substantiallygreater lifting forces can be achieved with the same use ofspace.

In a preferred embodiment of the invention, the axes of the cylinderbores are arranged perpendicularly to the direction of movement of thevalve plate, and the control pistons each have, at one end, a conicalcontrol surface on which the associated lifting piece is supported. Thisform of construction can be easily manufactured, because the cylinderbores can be provided radially in the peripheral face of the valve seat,and is distinguished by a particularly low space requirement, only aslight structural height being necessary for the valve seat. Inaddition, the radial arrangement of the cylinder bores simpli fies thesupplying of the pressure medium. A desired transmission ratio mayeasily be established by selecting the inclination of the conicalcontrol faces at the ends of the control pistons. The lifting piecesadvantageously consist of balls, which can be obtained cheaply and whichcause only relatively low-frictional forces during the lifting movement.

The control pistons may be of hollow construction and may each containin their interior a return spring by which they are restored to theiroriginal position after the control pressure has been cut off. In manycases, however, the closing forces acting upon the valve plate may alonebe sufficient for returning control pistons. The return springs may beseated in blind bores at the end face of the control pistons which isopposite the end of the piston which is acted upon by the pressure. Thereturn spring may conveniently be supported at one end against theinside of the pressure-loaded end wall of the hollow control piston, andat the other end against a pressure pin which projects from the controlpiston and is continuous with the base of the cylinder bore containingthe piston. In this case, the control pistons are expedientlyconstructed in two parts, and each consist of a hollow cylinder, whichis sealed at one end, and a cap which is fitted on to the open end ofthe said cylinder and is preferably provided with the inclined controlface. The control pistons then form, together with their return spring,a self-contained component and which can be inserted and removed easilyand quickly.

BRIEF DESCRIPTION OF THE DRAWINGS Further details of the invention arenow described by way of example with reference to the accompanyingdrawings, which show, in FIG. 1, a compressor valve according to theinvention in axial cross section, in FIG. 2, an enlarged detail of thevalve and, in FIG. 3, a partially diagrammatic detail of another form ofvalve arrangement.

DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows the upper part of acompressor having a cylinder sleeve 1 and a piston 2. On a flangelikeedge of the cylinder sleeve 1 is fitted an annular induction valve 3,which, together with the cylinder sleeve 1 is fastened in a suspendedmanner on the compressor casing 5 by means of screws 4. Disposedconcentrically inside the annular induction valve 3 is a pressure valve6 which is only shown in section and is pressed on to its seatingsurface, formed by the induction valve 3, via a pressure part 7 and bymeans of a spring 8 which is braced against a cover 9. The inductionvalve 3 has a valve seat 10, with flow channels 11 controlled by a valveplate 12 consisting of a single ring, and also has a catcher l3 and,braced against the latter, more annular plates 14, particularly one ormore spring plates, which press the valve plate 12 on to the valve seat10.

In the valve seat 10 and distributed over the periphery thereof, thereare provided a plurality of cylinder bores 15, for example eight innumber, which start at the outer surface of the valve seat 10 and extendin the radial direction so that their axes are inclined at a right angleto the direction of movement of the valve plate 12. In the cylinderbores 15 are disposed control pistons 16 which, at their inner end, havea conical control face 17, on each of which a ball 18, which serves as alifting piece, is guided. The balls 18 lie below the valve plate 12 andform a driving connection between the control piston 16 and the valveplate 12. A channel 19 is formed in the compressor casing 5 forsupplying a pneumatic or hydraulic pressure medium to the cylinder bores15, and opens into a sealed-off annular groove 20 which is left betweenthe induction valve 3 and the compressor casing 5 and which surroundsthe valve seat 10, thus providing a supply of pressure medium to thecylinder bores 15.

In use, pressure medium supplied through the channel 19 and the annulargroove 20 acts upon the control pistons 16 and displaces them radiallyinward. During this process, the balls 18 slide along the conicalcontrol faces and are lifted by the latter against the valve plate 12 sothat this is raised from the valve seat 10. The induction valve isthereby held open until the pressure acting upon the control pistons 16is reduced, whereupon the latter return to their original position,either due partly to the closing forces acting on the valve plate 12 orwith the aid of return springs of their own. Depending upon theinclination of the conical control face 17 relative to the axis of thecontrol piston 16, the ratio between the adjusting movement of thecontrol piston and the lifting movement executed by the ball 18 isdetermined.

The control piston 16 illustrated in FIG. 2 is of hollow constructionand is provided with a return spring 21. In this case, the controlpiston consists of a hollow cylinder 22, which is closed at one end, anda cap 23 which is fitted on to the open end of the said cylinder and isbevelled to form the conical control face 17. The return spring 21 isbraced at one end against the inside of the end wall of the hollowcylinder 22 and at the other end, against a pressure pin 24 which passesthrough the cap 23 and is continuous, at its outer end, with the base ofthe cylinder bore 15. There is thus formed a compact structural unitwhich consists of the control piston and return spring and isdistinguished by simple manipulation and a low space requirement.

FIG, 3 shows a form of embodiment in which the cylinder bore is inclinedat an acute angle in relation to the direction of movement of the valveplate 12. In addition, the control piston 16' in this case actsdirectly, without the interposition of a lifting piece, upon the valveplate 12, the control face 17 sliding on the underside of the valveplate 12 during the adjusting movement. This embodiment, too, isdistinguished by a low space requirement, while, in the exampleillustrated, the cylinder bore 15 intersects with the flow channel 11 inthe valve seat 10 so that, because of the arrangement of the controlpistons 16', there is practically no loss of flow cross section in thevalve. Furthermore, as with the exemplified embodiment in FIG. 1, anadvantageous ratio between the adjusting movement of the control piston16 and the lifting movement of the valve plate 12 is achieved, the sizeof which can be determined according to choice by selecting the angle ofinclination of the cylinder bore 15.

The devices for regulating delivery quantities shown in the exemplifiedembodiments may be applied with equal advantage both to induction valvesand to pressure valves.

I claim:

1. A compressor valve arrangement comprising a valve seat having flowchannels therein controlled by a valve plate, spring means arranged topress the valve plate on to the valve seat and lifting means arranged toraise the valve plate from the valve seat against a closing force actingupon the valve plate, wherein the lifting means comprises controlpistons displaceable in cylinder bores in the valve seat, each of saidcon trol pistons being of hollow construction having a control faceinclined in relation to the piston axis in driving connection with thevalve plate and further having a pressure-loaded end wall spaced fromsaid control face, a pressure pin within each piston and projectingoutwardly therefrom in contact with the base of each respective cylinderbore, a return spring within each piston, one end of the return springbearing against said pressure pin and the other end of said returnspring bearing against the inner surface of said pressure-loaded endwall, and the cylinder bores being disposed in the valve seat with theiraxes inclined to the direction of movement of the valve plate.

2. An arrangement as claimed in claim 1 wherein a lifting piece isinterposed between said face of each piston and the valve plate. I

3. An arrangement as claimed in claim 2 wherein the axes of the cylinderbores are perpendicular to the direction of movement of the valve plate,and the face of each of the control pistons is a conical control surfaceon which the corresponding lifting piece is supported.

4. An arrangement as claimed in claim 2 wherein the lifting piecesconsist of balls.

5. An arrangement as claimed in claim 1 wherein each control pistonconsists of a hollow cylinder sealed at one end, a cap fitted on theopen end of the said cylinder, said inclined control face being definedby said cap, and said pressure pin projecting through said cap.

1. A compressor valve arrangement comprising a valve seat having flowchannels therein controlled by a valve plate, spring means arranged topress the valve plate on to the valve seat and lifting means arranged toraise the valve plate from the valve seat against a closing force actingupon the valve plate, wherein the lifting means comprises controlpistons displaceable in cylinder bores in the valve seat, each of saidcontrol pistons being of hollow construction having a control faceinclined in relation to the piston axis in driving connection with thevalve plate and further having a pressure-loaded end wall spaced fromsaid control face, a pressure pin within each piston and projectingoutwardly therefrom in contact with the base of each respective cylinderbore, a return spring within each piston, one end of the return springbearing against said pressure pin and the other end of said returnspring bearing against the inner surface of said pressure-loaded endwall, and the cylinder bores being disposed in the valve seat with theiraxes inclined to the direction of movement of the valve plate.
 2. Anarrangement as claimed in claim 1 wherein a lifting piece is interposedbetween said face of each piston and the valve plate.
 3. An arrangementas claimed in claim 2 wherein the axes of the cylinder bores areperpendicular to the direction of movement of the valve plate, and theface of each of the control pistons is a conical control surface onwhich the corresponding lifting piece is supported.
 4. An arrangement asclaimed in claim 2 wherein the lifting pieces consist of balls.
 5. Anarrangement as claimed in claim 1 wherein each control piston consistsof a hollow cylinder sealed at one end, a cap fitted on the open end ofthe said cylinder, said inclined control face being defined by said cap,and said pressure pin projecting through said cap.